1. Technical Field
The present invention is related to an apparatus and method for defining a pattern on a substrate using a shadow masking technique.
2. Prior Art
The shadow masking technique as well as inclined exposure and deposition are well known and allow efficient fabrication of patterns by replacing the conventional lithography cycle comprising deposition, photo and etch process steps by just one single process and machine. A main disadvantage of the traditional shadow masking technique is its limitation to simple low density patterns. Up to now it has not been possible to define more complex patterns, such as ring type patterns, or to produce patterns in close proximity to each other with sub 100 nm dimensions by shadow masking technique. Inclined exposure and deposition allows definition of very small single features, but the close proximity of patterns cannot be achieved by inclination.
V.T. Petrashov, Microelectronic Engineering 35 (1997) p. 357-359 reflects the state of the art. The technique proposed there allows fabrication of more complex patterns and elements with dimensions of less than 50 nm. This is achieved by a lift-off technique using self narrowing of atomic beams and in-situ rotation of the substrate. The lift-off technique is a special form of photo lithography and therefore different from the shadow masking technique. It has not the simplicity of the shadow masking technique because it includes a photo step as well as final removal of photo resist and excess material (the so-called lift-off).
It is an object of the present invention to overcome the disadvantages of prior art systems and to define patterns of complex shape in close proximity to each other with sub 100 nm dimensions.